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A212850 Number of n X 3 arrays with rows being permutations of 0..2 and no column j greater than column j-1 in all rows. 2
1, 19, 163, 1135, 7291, 45199, 275563, 1666495, 10038331, 60348079, 362442763, 2175719455, 13057505371, 78354598159, 470156286763, 2821023814015, 16926401164411, 101559181827439, 609357415487563, 3656151466494175 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 3 of A212855.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 10*a(n-1) -27*a(n-2) +18*a(n-3).

Explicit formula: a(n) = 6^n-2*3^n+1. - Vaclav Kotesovec, May 31 2012

EXAMPLE

Some solutions for n=3

..1..2..0....2..1..0....0..2..1....1..2..0....1..2..0....2..1..0....1..2..0

..2..0..1....2..0..1....2..0..1....2..0..1....0..2..1....2..0..1....1..0..2

..0..2..1....0..1..2....2..1..0....2..1..0....2..0..1....0..2..1....0..2..1

CROSSREFS

Sequence in context: A217215 A159682 A197500 * A215115 A142128 A158966

Adjacent sequences:  A212847 A212848 A212849 * A212851 A212852 A212853

KEYWORD

nonn

AUTHOR

R. H. Hardin May 28 2012

STATUS

approved

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Last modified March 23 02:49 EDT 2017. Contains 283901 sequences.